as phat says, your premise is faulty.
Why? what is evil to god? what is good? very few claim to understand the nature of god, so why are you putting your views on god?
oh, and the genocides were good, so is deforestation, so was the slave triangle, so have all the massacres and forced migrations ad infinitum. (note: I do not think so) It all depends on who you ask. so clearly there is not even an absolute definition as to what is evil or not. and your premise really relies on absolutes.
another problem--does evil = wrong? not every time, i would argue. It is wrong of me to skip class, but is that evil? It is wrong of me to stereotype people, yet is that evil? Is it wrong to kill people, or evil too? Because god has killed a lot of people (assuming OT god here). But the act wasn't evil in nature--he was ridding the world of evil.
a better premise would be:
P)god never does evil
P)god does X
C) X is not evil.
you have a twice faulty syllogism (and yes, my update is also faulty, because it relies on an absolute definition of what is evil, when such does not exist).